When conducting repair work wooden floors, owners of apartments and country houses often cover the old base with plywood sheets.
Such repairs are quite economical, simple and do not require special skills.
Let us consider in more detail the options for repairing a wooden floor, what kind of sheet material to choose for this and how to lay plywood on wooden floor.
Material properties
Thick plywood can last for years Plywood is a fairly versatile material.
Due to the ease of processing, cutting and laying, in a short time, with the help of sheets, you can lay a fairly durable floor covering.
With all this, the material is economical, practical and has other advantages:
- non-toxic, does not emit foreign unpleasant odors;
- has a small weight, but high strength;
- does not break when bent, elastic;
- easy to transport;
- has a beautiful front surface;
- sheet dimensions make the work on laying a new coating low-cost in time;
- budgeting;
- a huge selection of material in any hardware store.
When choosing plywood as a future floor covering, it is important to buy the right and suitable material, make no mistake in it physical properties. This type of material also has its drawbacks.
Like any wood-based coating, plywood does not like high humidity, requires getting used to the operating conditions before installation, capricious in storage.
Plywood does not crack when dry
A sheet is made by gluing several layers of wood under pressure. Depending on the number of layers, as well as the substance of the adhesive and impregnation, the properties of the resulting material vary.
What plywood of any grade will have in common is increased anisotropy or even distribution properties. physical activity on the news the volume of the plate. At the same time, the material does not crack during drying and is not prone to deformation. 
It is these qualities that make plywood an indispensable material for floor repair. All manufactured material is divided according to grades, surface quality and moisture resistance.
Sheet marking values
| Marking | Designation | Characteristic |
|---|---|---|
| Variety | E, I, II, III, IV | Indicates the structure of the sheet gluing, the quality of the front and back layers |
| moisture resistance | FSF | Possesses increased level water resistance, strength and wear resistance. Not used in residential areas, releases toxins. |
| FC | Not highly resistant to moisture, but will remain intact when exposed to water for 24 hours. | |
| FKM | Increased water resistance | |
| FBA | Suitable for children's, living rooms, bedrooms. 100% environmentally friendly product. Will not withstand prolonged high humidity. | |
| Surface quality | NSh, Sh1, Sh2 | not polished; polished on one side; sanded on both sides. |
| Environmental friendliness (formaldehyde level) | E1, E2, E3 | E1 - no more than 10 mg, E2 - from 10 to 30 mg |
Any other numbers and designations indicate that the goods are rejected and do not comply with GOST.
Suitable material
What kind of plywood to lay on the floor depends on many factors:
- lay sheets on top of the old coating;
- laid on the logs;
- used as finishing or as a leveling base for decorative material.
For the floor, choose birch sheets that are stronger than other species It is important to understand which plywood is best to use for various types works. For the floor on the logs, as well as for the base under roll material, it is better to choose birch sheets, they are more solid.
As a leveling base, in order to save money, it is appropriate to use grade 3 or 4 unsanded material.
Under a hard decorative coating: laminate, parquet, plywood can be used conifers. For grouting, putty is selected to match the color of the selected material: birch or pine needles.
To level the base, use sheets with a thickness of 1 to 1.5 cm.
Before buying, draw a diagram of the flooring and cutting of plywood in order to optimally select the dimensions of the sheets and reduce the amount of waste.
Preparation and laying on old boards
Before laying plywood on the floor, the material should be allowed to rest indoors at room temperature and humidity not more than 55% for several days.
Sheets are always placed in a run: that is, with a seam offset, at least 1/3 of the side.
There should be a gap of 10 mm between the wall and the plywood layer: plywood is a living material, therefore, in order not to spoil the decorative coating, it must be allowed to breathe.
On old floor boards, the material can be put on glue If it is decided to lay the boards on the boards of the old coating, then they should be carefully fixed. It is necessary to fasten the boards to the joists so as to get rid of squeaks and deflections.
The slab should be screwed to the floor with self-tapping screws, fixing along the perimeter and diagonally in increments of 15 - 20 cm.
Installation starts from the wall opposite to front door. During the entire process, be careful that the sheets do not form waves. Seams should be sealed with acrylic-based putty.
If the plywood is to be processed as decorative coating, then it is better to lay polished material high grade, rubbing the seams with wood-colored putty, which must be sanded after drying.
Laying plywood on logs
When laying on logs, you can at the same time insulate and waterproof the floor If it is possible to remove the old wood flooring, then it is better to do this and lay the sheets on the logs. In this case, you can check the strength of the coating structure and, if necessary, strengthen it.
It is also possible to carry out additional measures that improve hydro and thermal insulation, which is important for the floors of the 1st floor. When laying sheets on beams, you should calculate the distance between the lags so that one sheet falls on at least 3 guides. See this helpful video for all the details of the process:
To give additional rigidity, you can mount the crate by making jumpers from the bars between the lags. Carefully fix the sheets with self-tapping screws on the logs.
When laying, the sheet should not sag under the weight of a person, otherwise, during operation, the putty from the seams will begin to collapse, which will cause deformation of the upper decorative coating.
Advantages of plywood coating
Plywood flooring is considered by most experts to be a good alternative. concrete pavement for the floor.
This option eliminates the hard work of leveling the screed, laying does not take much time, and at the same time plywood will serve as additional insulation.
In addition, it is a warm and pleasant material to use.
Unlike boardwalk installation of plywood is economical in terms of money, time and does not require special skills.
The disadvantages include the need for additional processing of sheets or laying decorative material. Be careful when buying, remember that not all plywood is suitable for flooring in residential premises due to the level of environmental friendliness.
Leveling the floor with plywood sheets is a quick and easy procedure that requires minimal cash outlay. The effectiveness of this method in practice is quite high, so plywood flooring is very popular. One of the advantages of the material, experts recognize the small thickness of the sheets, which allows you to work in rooms with low ceilings. How to lay plywood on a wooden floor and a concrete base?
Main characteristics of plywood
Plywood as a material has a number of important advantages, due to which it is most often used for leveling floors for decorative coating. The plywood sheets have different format, have a high level of reliability and durability. The material is convenient to transport, installation plywood cover also not difficult even for a beginner.
Among the qualities of plywood, it should be noted a high degree stiffness and strength, material good quality durable. Sheets have some flexibility, which has special meaning during installation of the cover. All these qualities, together with affordable price make plywood an indispensable material in construction.
The sheet surface is different. high quality polishing, there is no unpleasant smell, which is an important quality for residential premises. Usually plywood smells like wood, there are no chemical components. The material is resistant to high moisture content, so it can also be used for floors in rooms where humidity is always at high level. With the help of plywood sheets, the floors are leveled not only in the corridor and kitchen, but also in the bathroom.
Durable and solid plywood sheets weigh a little, it is convenient to mount them yourself. Cutting and any other processing source material also not difficult: special training not required. If necessary, plywood sheets can be bent without fear of getting ugly cracks on the surface of the material.
How to lay the sheets on the floor? Plywood is chosen by thickness: preference should be given to sheets with a thickness of 12 or 16 millimeters. The opinion that plywood sheets are weak and not suitable for flooring for finishing is a delusion. Plywood is a multilayer material, the layers of which are laid perpendicular to each other. The strength of the sheet and its resistance to stress depend on the number of such layers. When choosing plywood in 9 or 11 layers of wood, the finished surface will not only be durable, but also ready for loads in the form of the weight of furniture and the movement of apartment residents.
When choosing plywood, pay attention to the type of surface, sheets can be sanded and unsanded. Among the brands, it is necessary to give preference to those that have already proven themselves in the building materials market and are distinguished by increased water resistance of the adhesive. Of the four plywood grades, the first grade is the best: there are no external defects on the surface of the first grade material except for microcracks, and the plywood itself is characterized by the most high rates quality.
Laying sheets on concrete
The flooring of plywood sheets as a subfloor can be carried out directly on a concrete base - right along the screed. How to lay plywood in this case? Sheets can be laid on a concrete floor only if the screed is of high quality. The base must be level and decorative finishes use linoleum or cork.
Before installing plywood, the working surface is thoroughly cleaned of debris, then experts recommend covering it with bituminous varnish with the addition of kerosene. This processing can only be done open windows and power outages. For work, sheets up to 1.8 cm thick are selected, installation is carried out in a run-up in the form of stripes or squares. When carrying out work, it is important to remember that the seams between the sheets should not converge in one place - lay them with an offset according to the principle brickwork. Between the plywood layer and the walls, it is necessary to leave gaps of a couple of centimeters.
If in the future you plan to make a top coating of linoleum, then plywood can be attached to a concrete base on bustilat or parquet mastic. In this case, there should not be any gaps at the end of the installation. If as a decorative topcoat will act parquet board, then the draft layer of plywood can be fixed with self-tapping screws, leaving mounting seams.
How to lay plywood on self-tapping screws? A sheet of material is laid on the concrete floor, on which holes are drilled in the corners, diagonally and in the central part - with an offset. Then the sheet is shifted, and holes for dowels are made in the marking places in the concrete base. The base under the sheet is smeared with an adhesive solution, the plywood is laid in its place and attached with self-tapping screws, the caps of which must be placed in the wood.
Similar work on leveling floors with plywood can also be carried out on a wooden base. Another way to install plywood flooring is to lay it on pre-prepared logs.
Plywood flooring on logs
Laying plywood on logs is carried out in cases where it is planned to use laminate or parquet as the final coating. In order for such a coating to last long enough, you must first make a crate.
How to lay plywood on a wooden floor? First, a crate of logs is erected on the base, and the resulting sections are filled with thermal insulation. As a heat-insulating layer, you can choose any suitable material, the main thing is that it must meet the requirements of environmental friendliness, as it fits in a residential area.
The frame boards are fastened with self-tapping screws in increments of up to 60 cm. The logs should be placed so that the edges of each plywood sheet fit on them. Between the elements of the upper plywood layer, small gaps of 2 mm should be left, the distance to the gaps from the walls is the same as in the case of concrete base should be a couple of centimeters. The sheets themselves can be attached to the lag frame with liquid nails.
As a result of leveling work with plywood, you will get an even surface, ready for finishing. Using the method of attaching plywood sheets to logs can be implemented on any basis: both concrete and wooden. This method of work allows not only to make a warm, even floor, but also, if necessary, to install a heating system, place communications under the floor, and protect the basement of the house from freezing.
Before laying plywood on wooden floors, consider possible options implementation of the leveling plywood layer. Sheets can also be attached directly to a wooden base without a batten from a log. This is done with nails. Mounting plywood on logs seems to be the most preferable, as it allows you to create a more reliable and durable structure.
The logs are made from well-dried boards, which have lain for about two weeks in the room where the work is carried out - this is necessary for the wood to “get used” to the surrounding conditions. The logs must be placed absolutely horizontally; during work, their position should be checked periodically with a level.
Wooden floors should be additionally protected from the accumulation of condensate. For these purposes, many use glassine, which spreads before starting the installation of the plywood structure. Glassine is a roofing paper impregnated with bitumen. This material, when arranging the floor, will play the role of waterproofing.
To make the construction of plywood more durable, sometimes its sheets are laid in two layers. In addition to self-tapping screws, it is recommended to use PVA glue as an additional fastener.
As a result, the finished floor should have the following layers: waterproofing material, lathing from logs, waterproofing on logs, plywood in one or two layers, finishing decorative coating.
When assembling a plywood layer, always keep an eye on three things:
- The edge of the plywood sheet should lie on the log;
- The corners of the sheets should not converge in one place - make an offset;
- There should be a small gap between the plywood sheets.
If all the requirements for laying plywood are observed, then the result of the work will be of high quality and durable.
Adjustable floors
When on working surface If the floor has large differences of 10 cm or more, then you can correct the situation with the help of adjustable plywood floors. This type of structure is called a raised floor and is also used in the presence of communications laid along the floor surface.
Mounting on adjustable lags. Regardless of whether we lay plywood on wooden floors or on concrete screed, there are only two options for implementing the design. The floor can be laid either with the help of adjustable logs, adjusting them to the required parameters, or with the help of adjustable plywood. If the ceiling height of the room allows you to take 8 cm of free space, then you can choose the first method of organizing plywood flooring. If the ceilings in the room are low enough and there are no extra centimeters, then only the second option remains, in which two layers of plywood will take only three additional centimeters.
When using the second method of plywood flooring for arranging adjustable floors, the first layer of sheets is attached to special bushings with internal thread, and the second layer - with screws to the first coating. The joints of the sheets of each of the layers should not coincide: laying plywood with an offset will increase the strength of the entire structure.
Adjustable plywood floors are quickly mounted, do not create additional debris, are reliable, practical and long term services. A flat and smooth surface can be used as an ideal base for laminate, linoleum or carpet.
We are coming to the end of our big topic of creating a high-quality, even and durable floor in an apartment. Today awaits us final stage- laying plywood on the floor. After that, any floor covering can be mounted on plywood, and here your imagination is completely: linoleum, carpet, laminate, parquet board, block parquet.
Laying plywood on the floor
Laying plywood on the floor is carried out in several successive stages, which we will now discuss.
Cooking plywood
We put the first sheet in the most flat corner leaving as always temperature gap 3-5mm between wall and plywood. Then we put the next sheet. While we do not fasten anything! At the end of the row, it is necessary to cut out an incomplete piece with an electric jigsaw (first we measure everything). In order for the joints to go in a checkerboard pattern, in the next row of plywood we lay a whole sheet opposite the cut one. Thus, we lay plywood over the entire floor area.
How to fix plywood?
We approach this process with the utmost care. Plywood should be one with the black floor. No gaps, otherwise everything will creak. Therefore, do not spare the screws, get ready to tighten their pieces of commercials in 2000 :).
Important!
Do not drive screws directly into plywood! Under each self-tapping screw, a hole with a diameter slightly smaller than the diameter of the self-tapping screw (countersink) should be drilled. Through this you will receive:
- Tightly drawn plywood to the boards.
- Perfectly flat plane. Plywood will not warp from a lot of self-tapping screws.
This is, of course, a rather laborious process. But if you want a flat floor, don't be lazy! Pick up a drill, screwdriver and go!
How to draw plywood?
It is possible in two ways.
- The first is the simplest, for lazy people. Approximately by eye, drill holes with the indicated pitch (10 × 15 cm). There is a big minus here - some self-tapping screws can get into the edge of the boards, or even they won’t hold between them at all!
- The second way is correct. While the plywood is lying on the floor, alternately lift each side of each piece and mark on the plywood the middle of each board lying under the plywood. Then, using a long ruler, we draw lines corresponding to the position of the boards under the plywood (with a step of 10 cm - our boards were just 10 cm wide). Next, we draw perpendicular lines with a step of 15 cm. We also make a number of self-tapping screws on the edges of the plywood.
Important!
Drilling is not done on lying plywood sheets in order to avoid drilling boards together with plywood. In order not to confuse the sequence of sheets, we mark each sheet, where and on which side it lay.
All plywood sheets should be primed. This will protect the plywood from possible moisture and increase the adhesion of parquet glue (if future parquet is supposed to be planted on glue). Prime the bottom of the plywood sheets before laying, the top - after the sheets are fastened with self-tapping screws.
We prepare a cork substrate for plywood
Plywood is ready. Now we clean the surface of the black floor - carefully sweep all the garbage. Then we roll out the prepared cork backing roll on the floor:
Cork underlay needed! It evens out all the micro-roughness of the boards and ensures a snug fit of plywood to them.
We put the cork neatly butt. And so that it does not move when laying plywood, we let a thin strip of PVA glue under the edges of the cork along the joints and near the walls. Then we press the edges of the cork (especially where they bulge) with the rest of the boards for 3-5 hours.
Attaching plywood to the floor
The cork is laid and the glue has dried. Now we lay the plywood. It's better to do it together and carefully.
Important!
If you hook the cork with a plywood corner, move it or tear it, everything is gone!
First, lay the first sheet of plywood in its place. When he already lies with the whole plane on the cork substrate, all the terrible things are over. The sheet can be gently moved, the cork will not move or tear, it is held by glue. Thus, we lay all the sheets of plywood according to the markings and fit them tightly together. If gaps of 1-2 mm remain, this will not damage the parquet.
We laid all the plywood, now we fix it with self-tapping screws. First we fix all the corners, then everything else in any order. The most important thing is to screw the self-tapping screw so that the cap is pressed into the plywood and is slightly below the plane of the sheet.
Important!
Avoid protruding hats. But do not immerse too deep - it can lead the sheets!
This is what plywood looks like:
Important!
Pay attention to the edges of the sheets - a line of self-tapping screws is required along the edge!
Boxes of self-tapping screws show how many were used. It took us about 2000 pieces for a room of 14 m².
We laid the plywood, now it remains to sweep it and cover it with soil.
This completes the laying of plywood on the floor:
Well, dear readers!
You have made a solid, high-quality basis for your future floor!
Plywood is one of the most versatile materials invented by mankind. Plywood is also widely used in construction: in terms of ease of working with it, strength, low cost and environmental friendliness, plywood is perhaps unmatched. Plywood is especially widely used in laying and repairing floors. But the high functionality of plywood also determines the variety of methods of working with it, so laying plywood on the floor with your own hands requires explanation for different cases of practice.
Chipboard or plywood?
Plywood is not the cheapest material for flooring and wall cladding. Chipboard is even cheaper. But let's leave alone for now phenol-formaldehyde resins - volatile carcinogens, on the basis of which chipboard is made.
Let's do the following experiment: put two pipe cuts on the floor and lay a sheet of plywood 12 mm thick on them. Let's get on it, let's go. What happened? Nothing. Bent over and straightened up. What about chipboard? Most likely, it cracked at a greater thickness. And it will definitely crack if you jump on it.
You can do two more experiments: hold plywood and chipboard trimmings in water and see how soon they swell and become limp. It is not necessary to knock on the edge with a hammer: everyone knows that chipboard is fragile. Therefore, the question: “chipboard or plywood?” definitely decided in favor of plywood.
What is plywood
There are many varieties of plywood. In construction, plywood of the following grades is most often used:
- FC - moisture resistant plywood on urea resin, non-volatile and non-toxic. It has strength and elasticity comparable to BS aviation plywood.
- NSh - unpolished on casein glue. The cheapest, about 170 rubles / sq.m with a thickness of 12 mm. Before gluing parquet or other hard flooring onto it, it requires sanding.
- Ш1 - the main material going to the subfloor. Sanded on one side. Adhesive base- also casein.
- Ш2 - polished on both sides, on casein. For lightly loaded parts in dry rooms and with comfortable temperature can be used as a substitute for FC.
What is contraindicated for plywood
Nothing is perfect, and plywood is made from a hygroscopic material - wood. Therefore, plywood cannot be used in damp rooms: long-term air humidity should not exceed 68%; short-term within 12 hours - 78%. When laying raw plywood, air humidity up to 60% is permissible.
The specified values are valid in a comfortable temperature range of 18-27 degrees Celsius. Outside these limits, the sensitivity of plywood, except for FC, to humidity increases: at 16 and 35 degrees and humidity of 85%, plywood begins to delaminate after two months. Therefore, ordinary plywood for floors and walls should not be used in the kitchen, balcony, closet, hallway and bathroom.
How to improve plywood
Moisture resistance of plywood can be increased by impregnation with putty based on polyvinyl acetate (PVA); it looks like very liquid PVA glue and is cheap. Impregnate first on one side until spots appear on the opposite side, then on the other twice. Dry in a horizontal position. It will take a long time to dry - at least 3 days at room temperature. After drying, the sheets are treated with any antiseptic fungicide for wood.
The strength of the surface layer can be increased acrylic varnish. It is applied in two layers; the second - after the complete drying of the first. If plywood for decorative purposes needs to be stained, paint before varnishing.
Acclimatization of plywood
Before describing how to lay plywood on the floor, it should be said about its acclimatization in the room. Plywood, like any wood material, requires acclimatization at the place of use. The term of acclimatization depends on the difference in temperature and humidity: if the conditions in the warehouse or in the store are the same as in the apartment, a day is enough; with a temperature difference of 2 to 8 degrees - three days; with more - a week. During acclimatization, the plywood is kept stacked in a horizontal position.
Subfloor Moisture Check
Before laying plywood on the floor, the base surface, and not only concrete, you need to check for moisture evaporation. For this 1 sq.m. base surface covered with a single square piece polyethylene film, pressing it along the edges with slats with weights and lifting the center a little. Further depends on the time of appearance of condensate under the film:
- The bubble fogged up from the inside during the day - the room is unsuitable for covering the floor with plywood.
- Small drops appeared within 3 days - the base concrete floor must be covered with glassine or plastic film, put a construction mounting grid on it and make a screed. Wooden floor - disassemble; with such evaporation of moisture, the boards from the underside and the old logs are probably touched by rot. An option for 7-10 years is to lay plywood with an improved home method (see above) moisture resistance.
- Condensation did not fall out on the 5th day: you can lay plywood in any way.
plywood base
Leveling the floor with plywood is a widespread building technique. It is used both for laying new floors and for express repairs of existing ones. For various combinations of base floors and top decorative coatings, different technologies plywood laying.
Concrete
Laying plywood on a concrete floor is possible both directly on the screed and on logs. The first method is used if the base floor is sufficiently even, and the finish coating is somewhat plastic; for example - under linoleum or cork floor. Marmoleum can be laid directly on the screed without a subfloor.
Important: remember that after the concrete has set, it must be dried for at least 40 days at room temperature.
On a flat dry screed
The room is thoroughly swept and vacuumed. The floor is treated with bituminous varnish or parquet mastic, diluted five times with solvent or kerosene (primerization). When working, windows are wide open, they work in a respirator-petal, and in the apartment completely, by unscrewing the plugs or turning off the machine on the floor panel, they remove the power supply: what is a spark in the air, saturated with steam organic solvent, no need to explain.
Plywood 8-18 mm is pre-cut into quarter squares standard sheet(1250x1250 mm) or stripes. Lay apart, i.e. with a shift: there should not be four seams converging at one point. Sheets are cut with a jigsaw or a manual circular saw - this can be done in next room one hour after priming. When cutting, it must be borne in mind that a gap of 20-30 mm should remain along the perimeter of the room.
Then the sheets of plywood are laid out on the floor, “dry”, adjusted and numbered without fastening. How to fix plywood to the base floor in this case? Under linoleum or cork, you can simply use bustilate-type glue or parquet mastic, without mounting slots - you get a floating subfloor. The ends of the sheets must also be glued.
Under ordinary oak or parquet similar in properties, plywood, along with gluing, is fixed with self-tapping screws 4-5x60 mm in dowels. In this case, sheets / strips must be laid out with mounting slots of 2-3 mm; For this, it is convenient to use halves of toothpicks:
Note: as a screwdriver insert for a drill, it is convenient to use the insert of a combination screwdriver (see figure above).
On concrete on logs
Under laminate, inlaid parquet or parquet from valuable breeds wood plywood on a concrete base is laid on. The same is done if the stability of the temperature and humidity conditions in the room is in doubt. The device of the draft plywood floor on the logs is clear from the figure, we will give only the necessary explanations:
- Boards for lags take unplaned 100 mm ("weaving").
- Boards for lags can withstand at least a week in the room where they will be used, after which they are culled: those that are warped by an arc are put on the bosses, and those that have been driven by a screw are completely rejected.
- Plywood is taken by FK or improved independently, with a thickness of at least 12 mm; better - 18-20.
- The preparation of the base floor is done in the same way as in the previous case.
- Lathing of logs is made in increments of 300-600 mm so that all edges of the plywood sheets fall on the logs.
- Sections of the crate are filled with polyurethane foam or other hydro- and heat-insulating material, but not mineral wool- from it, microscopic needles will inevitably appear in the air, irritating the respiratory organs.
- Plywood sheets are laid with a mounting gap of 2-3 mm and with a gap around the perimeter of the room of 20-30 mm.
- Attach plywood to the joists with liquid nails glue and fix with nails; fastening with screws this case The quality of the subfloor does not noticeably improve, but it is more expensive.
Note: in recent times tongue-and-groove plywood with a thickness of 12-20 mm appeared on sale especially for subfloors. It is produced in the form of sheets from 300x300 mm and strips from 300x600 mm. For a valuable parquet floor, this is the preferred option: the cost of a subfloor in this case will still be a small fraction of total cost materials, and the probability of leakage of moisture vapor from the bottom is reduced by an order of magnitude.
Repair of wooden floors with plywood
Plywood is an excellent material for repairing cracked wooden floors, creaky and squeaky. In this case, plywood is laid on a wooden floor in whole sheets from the door so that the most walked surface is solid. Scraps are allowed along the edge and into places under furniture. The plinth is removed as carefully as possible and then it is put back.
Plywood is taken from 12 mm thick. Installation is done with the usual gap of 20-30 mm around the perimeter, but without mounting gaps between the sheets. Sheets are laid on bustilate, liquid nails or any other mounting adhesive; the ends are also glued.
Such a floor made of “self-improved” plywood, painted with any floor enamel, lasts 20 years or more in the bedroom. But it is impossible to repair damp, swollen floors with plywood, with traces of rot and mold, and in rooms with biting biting on the walls is impossible. It is necessary to remove the old floor, look for and eliminate the source of moisture, and only then lay a new one.
Warm floor on plywood
Under plywood, they are laid on a concrete screed on a mounting grid with waterproofing on the base floor. There is one caveat here: the edges of the waterproofing film must be brought under the plinth. If they are muffled with a screed, then the evaporation from heating can concentrate in one place and cause delamination from moisture.
When installing a subfloor under a warm one on the logs, such a problem does not arise, but it makes no sense to complicate and increase the cost of work: a warm floor dries the room well. So it's easier to leave a kind of vent around the perimeter for water vapor.
Plywood innovations
Plywood flooring is a branch of construction engineering that seems to be far from over. In the age of composites and nanotechnology, the good old plywood does not retreat and finds new uses for itself.
Adjustable floors
These floors are used as a base for wood inlays and other fine, exclusive work. Plywood flooring - double, made of high quality plywood. In the sheets of the lower layer there are threaded sockets for bolts. The bolts are shaped: above the thread there is a flat flare in the form of a press washer, and above it is a neck 3/4 of the thickness of the sheet for a hexagon or with a cross slot.
The top sheet with holes for the necks of the bolts is placed on the screws screwed into bottom sheet bolts, and adjust with an open-end wrench or screwdriver. When using bakelized plywood, accuracy is achievable common surface quite mechanical.
Plywood parquet
But plywood parquet is an invention of craftsmen. In it, the forgotten skill was revived at a new level artistic sawing from plywood. The technology of plywood parquet is simple and accessible to anyone.
Laying plywood on the floor, material selection criteria, varieties, advantages and disadvantages, installation technology.
The content of the article:
Laying plywood on the floor is a simple process, but you need to know how to cut the material correctly, how to fit the finished sheets and how to use them to level the surface. An equally important issue is the quality of plywood. To choose it correctly, you will need to understand the varieties and find out where each of them is used.
The main types of plywood for the floor
Wood-laminated board (chipboard) - construction material, consisting of several layers of veneer glued together. Each layer is laid perpendicular to the fibers of the previous one, which increases the strength of the material. Be sure to select an odd number of layers - at least 3, the maximum is not limited. The thickness of plywood is selected depending on where it will be laid, the expected load and the required strength.
The generally accepted division of plywood according to moisture resistance:
- FC (moisture resistant). Veneer layers are glued with a urea compound. The production technology allows the use of such plywood in residential premises, except for those where the humidity is above the norm - bathrooms, kitchens, bathrooms.
- FSF (super moisture resistant). The layers of veneer are glued together with poisonous glue - phenol-formaldehyde resin. The material has high strength, wear resistance, resistance to mechanical damage. Such plywood is used mainly for outdoor work. It is forbidden to use in baths and saunas.
- FBA (environmentally friendly). Veneer layers are glued with casein albumin glue. The use of such plywood is limited only to dry rooms, as it is susceptible to moisture.
- FB (moisture resistant). It is impregnated with Bakelite varnish. The scope of application is wide. Plywood does not deteriorate even in conditions of high humidity.
- BS. Plywood made with alcohol-based Bakelite glue. The material has increased flexibility, strength, is not affected by mold, and is resistant to moisture.
- BV. The veneer sheets are bonded with a water-soluble bakelite adhesive. Plywood is strong and flexible, but not moisture resistant.
When buying material for the floor, you need to choose it correctly:
- Top grade (marking E). The material has no external flaws. Used as finish coat, including for the floor.
- First grade. Knots may be encountered on the surface, but they do not exceed 10% of total area sheet, the length of the cracks is no more than 2 cm. Such plywood is also used for finishing the floor.
- Second grade. On the surface there are chipped, knots, burrs, cracks. The length of cracks can reach 20 cm. The total amount of defects does not exceed 40%.
- Third grade. Gluing of layers - high-quality. Wormholes with a diameter of no more than 6 mm are acceptable. The number of defects on a sheet is no more than 9. Plywood is used for leveling, creating a rough base for finishing the floor.
- Fourth, lowest, grade. The gluing of the layers is of high quality, the diameter of the wormholes can reach 4.5 cm, the edge is uneven, there are many intergrown knots on the surface. Used for subfloor only.
Plywood can be laminated, sanded on both sides (Sh2), on one side (Sh1) and unsanded (NSh). It is divided into two classes according to the content of formaldehyde (milligrams per 100 grams of dry weight) - marking E1 and E2. In class E1 level harmful substance is 10 mg per 100 g, in class E2 10 - 30 mg per 100 g of dry leaf weight. Plywood marked E1 is preferable for indoor use.
Thus, the most the best option for the finished floor is birch plywood FBA-2E1Sh1 12-16 mm thick. It is safe for humans, affordable and perfect for further laying of parquet, linoleum and laminate.
Important! Do not purchase third grade plywood for the floor. Optimal combination price and quality for flooring with birch plywood of the second grade.
Criteria for choosing plywood for the floor
Affordable price, decent quality and environmental friendliness are the main characteristics of building materials that we always pay attention to. In order to finally decide on the question of which plywood to choose for the floor, you need to correctly assess your desires and capabilities.
When shopping, pay attention to the following points:
- Glue. It is used to join sheets of veneer together. Carbamide and formaldehyde are hazardous to health. They slowly evaporate. If inhaled, they can cause severe poisoning. Albumocasein and bakelite adhesives are safe for human health.
- Rates. If the price for plywood sheet suspiciously low, most likely these are low-quality products from China. She has bad performance characteristics, "ruffy" upper layer and poor edge handling.
- Marking. Shows the resistance of the material to moisture and what impregnations the wood has been treated with.
Advantages and disadvantages of plywood flooring
Wood-laminated boards have 4 positive qualities:
- Strength/wear resistance. The original purpose of plywood is to reinforce weak spots on the wooden floor. The layers of veneer are glued perpendicular to each other, resulting in a durable surface. The thicker the plywood for the floor, the stronger it is.
- low price. Plywood is made from veneer, whole pieces of wood are not used, there is little waste during production. Therefore, the material cost is low.
- Versatility. Plywood, especially of small thickness, easily takes rounded shapes. This is not possible with natural wood. Using plywood, you can create rounded structures, while the finished surface will never crack.
- Ease of installation. Plywood is easy to work with. It is easily cut with a jigsaw or a small hacksaw. Sawing can be carried out in any direction without fear of knots and burrs. With a tree, such manipulations are impossible.
The fear of moisture is due to plywood production technologies: water can get between the layers and seep deep into the sheet, destroying adhesive connection. Bakelized plywood is used for the manufacture of yachts. It resists moisture for a long time, but it is expensive. Therefore, it is irrational to use it for something other than shipbuilding.
Technology for mounting plywood on the floor
The plywood is laid on both a concrete and a wooden base, according to the principle of brick bonding with an offset, in order to avoid connecting the corners of four plates at one point. Standard size the sheet is too large to be laid entirely, so it needs to be cut into four parts, getting small squares of 60 x 60 cm. In addition to elementary convenience in work, it is possible to increase the number of damper joints that are necessary to compensate for deformations when exposed to heat and moisture on the floor .
Preparatory work before laying plywood
You will need a few tools to install plywood. This is a screwdriver and self-tapping screws for attaching the material to the base, a level for controlling evenness, a tape measure for marking and cutting, a jigsaw for high-quality sawing.
Another important point- the surface on which the marking and cutting will take place. It must be perfectly flat and stable. Work with electric jigsaw requires precise movements. If the cutting table is unstable, you will not be able to cut the plywood correctly.
Leveling the floor with plywood begins with work on the rough base. This material is sensitive to the quality of the base, so a level is required for work. With it, you need to check the base on which the plywood will be laid for evenness. With a slope of more than 1 cm per meter, you will have to resort to leveling.
If the floor is wooden and it is not planned to remove it, laying the log will be the way out. If plywood is to be laid on concrete, then you will have to do a good job of leveling it “like a testicle”. The room must be swept and vacuumed thoroughly before laying the plywood.
Further actions if the base is wooden:
- Check the floor for strength, identify old rotted floorboards and replace them with new ones.
- Walk on the floor with the level. If the difference is up to 1 cm per meter, when laying plywood, use a system of underlays (small pieces of plywood, with which you can achieve desired height) under sheets. If the difference is significant, it is best to remove the old coating completely and pour a self-leveling concrete screed. True, it will take more than a month to wait until it is completely dry and gains working strength.
- Second leveling option wooden base before laying plywood - log system. It can also be used on a flat base, if in the future it is planned to lay a wooden floor, laminate, carpet, linoleum.
The work is done like this:
- Clear concrete slab from debris and dust.
- Knock down protruding bumps, repair places cement mortar.
- “Clog” the sinks with cement mortar. Let the floor dry, treat with a deep penetration primer on concrete to enhance adhesion between the subfloor and the future cement screed.
- Mark the floor into approximately equal squares. Use beacons for this. Attach them to gypsum mortar and set it to the correct level.
- Shut dry cement mixture water according to instructions. Use a drill with a mixer attachment to knead.
- Lay out the solution in a square that is located in the far corner of the room, level it with a rule and bring it to smoothness with a trowel.
- When the solution sets, remove the beacon extreme to the wall and fill the new square with the solution.
- Repeat the steps until the entire floor area is covered with a new screed.
- Wait 28 days until the new surface has gained working strength and is completely dry.
Fitting and cutting sheets of plywood for the floor
This step also applies to preparatory work and consists of several required steps:
- Measure the area of the room.
- When cutting, consider the presence of damper gaps of 3-4 mm between sheets of material and one centimeter near the walls. If this is ignored, then temperature changes and moisture ingress will lead to “swelling” of the base.
- Try on plywood - lay it without fastening as it will be laid in the final version. Lay sheets with a shift of vertical seams according to the brickwork method. The joints between them should fall in the middle of the log.
- After fitting, number the material.
Important! Be sure to check for defects, if the sheets delaminate, then replace them.
Floating fixation of plywood on the base
There are two options for mounting wood-laminated boards on concrete - floating directly on the base and along the logs.
Mounting technology:
- Dedust the leveled base.
- Fold the cut and numbered plywood in a stack in order of sheets.
- Glue the back side of the sheet with glue (pine resin should be part of the glue).
- Lay the plywood smeared with glue in the right (or left) far corner and press it to the floor.
- Drill holes with a puncher in each corner of the glued plate (for the length of the dowel).
- Insert a dowel into the hole and hammer it in.
- Repeat the same with the rest of the sheets.
- Seal the joints between the sheets with wood putty, glue them on top with mounting tape.
Fastening plywood to the logs
This is the easiest way to level the base. Plywood 0.5-1 cm thick can be used as a log, or you need to purchase a beam with square section 2 x 2 cm.
We fix the lag system in the following sequence:
- Make markings on the floor to install the lag.
- Attach them to this markup using special wood glue and self-tapping screws. If there are gaps between the floor and the joists, fill them with pieces of plywood that are suitable in thickness, having previously lubricated both sides with glue.
- Make a crate. The dimensions of each cell must match the dimensions of the plywood sheets.
- Fill in vacancies between the draft and finishing floor with insulation.
Watch a video about installing plywood on the floor:
Now you know everything about how to level the floor with plywood. Always use a level when working. Use it to level the rough base and install the logs. Plywood - comfortable material for further finishing, in addition, it provides good additional thermal insulation and dampens part of the noise.
